New Study: Diet Drinks May Actually Help You Lose Weight

The name seems to say it all: Diet Coke. But as we all know, in the murky world of food labeling, sometimes the words on the outside of a package don't match what's inside. One nutritional claim that has long been debated by scientists involves diet sodas. Do they help people lose weight? Or, as some researchers have reported, are the non-sugar sweeteners they contain actually false friends that stimulate appetite and encourage us to eat more?

To find out, scientists in Colorado and Pennsylvania divided a group of 303 obese adults (average weight: 205 pounds) into two groups. One group drank only water, while the others were encouraged to consume at least three servings of a diet soda, tea, or flavored water each week. After 12 weeks of following the same diet and exercise plan, the two groups weighed in: The diet-soda drinkers had shed an average of four pounds more than those who drank just water (9 pounds for the water drinkers versus 13 pounds for the diet-soda drinkers). That's not a huge difference, but it's certainly significant. The dieters who lost the most also reported feeling less hungry, suggesting that the artificial sweetener in their sodas satisfied their cravings without adding calories.

"This study clearly demonstrates diet beverages can in fact help people lose weight, directly countering myths in recent years that suggest the opposite effect," said coauthor James O. Hill, executive director of the University of Colorado Anschutz Health and Wellness Center. "Myths" is Hill's rather smug way of referring to the work of other scientists, some of whom have already commented that this research, though large in scale, didn't go on for long. Observers also note that the water drinkers weren't told to give up all nonsugar sweeteners, just those in beverages, so a closer look is needed to determine the exact role of low-calorie sweeteners in weight loss.

Finally, a note about the sponsors. The diet-soda study was paid for by the American Beverage Association, a trade group that represents both the makers of diet sodas and bottled water. Sounds like a win-win situation for them.